<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group appear name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in levelList" :key="item.path">
        <span v-if="item.redirect === 'noRedirect' || index === levelList.length - 1" class="no-redirect">{{ item.meta.title }}</span>
        <a v-else @click.prevent="handleLink(item)">{{item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script lang="ts">
  import {ref, defineComponent, watch, Ref} from "vue";
  import {useRoute, useRouter, RouteLocationMatched} from "vue-router";

  export default defineComponent({
    name: "BreadCrumb",
    setup() {
      const levelList: Ref<RouteLocationMatched[]> = ref([]);
      const route = useRoute();
      const router = useRouter();

      const isDashboard = (route: RouteLocationMatched): Boolean | string => {
        const name = route && (route.name as string);
        if (!name) {
          return false;
        }
        return name.trim().toLocaleLowerCase() === "Dashboard".toLocaleLowerCase();
      };

      const getBreadcrumb = (): void => {
        let matched = route.matched.filter(item => item.meta && item.meta.title);
        const first = matched[0];
        if (!isDashboard(first)) {
          matched = [
            ({
              path: "/dashboard",
              meta: {title: "概览"}
            } as unknown) as RouteLocationMatched
          ].concat(matched);
        }
        levelList.value = matched.filter(
          item => item.meta && item.meta.title && item.meta.breadcrumb !== false
        );
      };

      getBreadcrumb();

      watch(
        () => route.path,
        () => getBreadcrumb()
      );

      const handleLink = (item: RouteLocationMatched): any => {
        const {redirect, path} = item;
        if (redirect) {
          router.push(redirect.toString());
          return;
        }
        router.push(path);
      };

      return {levelList, handleLink};
    }
  });
</script>

<style lang="scss" scoped>
  .app-breadcrumb.el-breadcrumb {
    display: inline-block;
    font-size: 14px;
    line-height: 50px;

    .no-redirect {
      color: #97a8be;
      cursor: text;
    }
  }
</style>
